1630s, "any sticky substance," from Middle French gluten (16c.) or directly from Latin gluten "glue" (see glue (n.)). Used 16c.-19c. for the part of animal tissue now called fibrin; used since 1803 of the nitrogenous part of the flour of wheat or other grain; hence glutamic acid (1871), a common amino acid, and its salt, glutamate.

(glt'n) A yellowish-gray, powdery mixture of plant proteins occurring in cereal grains such as wheat, rye, barley, and corn. The gluten in flour makes it ideal for baking, because the chainlike protein molecules of the gluten trap carbon dioxide and expand with it as it is heated. Gluten is also used as an adhesive and in making seasonings, especially monosodium glutamate (MSG).